Boring mechanism



w. A. JENNpNGs BORING MECHANISM Filed Feb. 24, 1925 y of Figure 1.

Patented June 26, 1928.-

s* Ars S.

PATENT kwie BORING MncHANrsM.

Application filed February 24, 1925. Serial No. 11,084.l

This invention relates to that type of boring apparatus utilizing a central guide post or bearing within the cutter head and is an improvement over fmy application for patent for boring apparatus, iiled December 3, 1923, Serial No.' 678,186, Patent No. 1,549,985, Aug. 18, 1925.` One ofthe objects of the present invention is to produceboring apparatus substantially similar to the apparatusy shown in said application but differing therefrom in that provision is made for the boring of tapering passages in accordance with apattern formed by the central bearing or guide post.

Another object is to produceboring apparatus of such nature that the bits maybe adjustably disposed to bore straight passages of greater diameter than the normal capacityk of avparticular bit.k

A further object is to produce boring ap'- paratus of strong, durable, .efficient and inexpensive construction;y and in order that it may be fully understood, reference to be had to the accompanying drawing, in

which :-,-V i

Figure 1 is a central vertical section taken through a boringr apparatus embodying the invention as it will appear when in ruse in lboring a passageway formed with irregular or tapering walls. p Figure 2 is a side view of the tool. f v Figure 3 is a section on the line IIIfIII Figure if isv a bottom Vplan view of the 'tool as shown in Figure 1.

In the said drawing, where like yreference characters` identify corresponding parts in all of the figures, 1 indicates a bed or other suitable rigid support Yand removably mounted on said support is a guide post or pattern 2 forming a central bearing and illustrated as varying in diameter at different points in its length. Resting on the bed and concentric with the post is a tubular supporting member 3 for a cylindrical piston, the hub of a pulley or other tube 4,-the inner surface of which is to be bored in accordance with the pattern formed by the central post 2,-is securely fixed against rotation in any suitable manner.

The cutter or boring tool comprises a hollow drive shaft 5 of greater diameter than the guide post 2 and having a suitable bearing at its upper end (not shown), axially alined with the guide post and adapted to be rotated and moved longitudinally by any VAsuitablesource of power, such as, fory eX- ample, a drill press Ory-the like. The lower en d of the drive shaft is threaded or otherwise secured to a collar 6 of a cutting head. Secured to said collar and projecting downwardly therefrom are two pairs of arms 7, each pair of arms carryingl at their lower ends` a cutting sector 8. The arms Iv are more or less resilient and when unimpeded the ends of the sectors abut and fo-rm a bearing somewhat vsmaller in diameter than .thediameter of the guide post, and in order j-to slip the driving head over vsaidpost, it

is necessaryto expand the sectors. The sec- .tors'are expanded by forming on each sector near one of its ends, an internallythreaded boss 9 engaged by a socketed screw 10 which `will press lat its `end against Athel adj acent arm 7 of the opposed sector (see Figure 2).

In the lower faces of the sectors a series of radial oppositely arranged slots ,'11 are formed, and `snugly received within each of said slots is a cutting bit 12, the bits being held in position by a pair of clamp or cover plates 13 secured to the lower faces of each sector by screws 14. K v.

' Vhen the tool is to be used to produce an 'irregular-passageway, the Lsectors are eX- panded by the use of the screws 10 until the driving heady will readily passover the desiredpattern andbearing post 2, the slots 11 being preliminarily fitted with suitable bits 12 which are free to slide in the slots. In this connection, it 'is to rbe pointed out vthat the boring operation may be carried yo'utrvertically downwardly or upwardly as desired, and as illustrated in Figure 1 the operation is'u'pward. In order to prevent the bits from accidentally catching or binding on the central post or against the wall being bored, the .inner ends of the bits are beveled' as at 15 and the outer corners are also'beveled as at'16 to forma round nose bit for boring irregular surfaces and also to aid in starting the boring operation of the bit. l

With' the bits freely sliding as described, it will be evident that as they abut at their inner ends .against the guide post 2, they will travelinwardly and outwardly in accordance with the pattern formed on the post,

and will reproduce on the inner face of the cylinder being bored a surface corresponding exactly to the surface of the post. The bits move inwardly due to the resistance oered by the cylinder wall being cut, provided the distance between the said wall and t-he post in the horizontal plane of the bits is less than the length of the latter, and conversely the bits move outward las the eX- panding diameter of the post forces them in that direction and hence cause. themv to make a cut of increasing depth in the wall of the cylinder. i

If it is desired to bore a straight cylinder',`

a straight sha-ft 2 is substituted forv the irregularjshaft illustrated, and the screws are unscrewed to permit the arms 7 to contract unt-il the inner faces of the .sectors 8 are properly .seated on the guide post, it being understood that as the sectors are of smaller diameter than the post, they will seat on the posts only adjacent their ends as set out in my application above cited. vBits of the proper length are now inserted in the slots 1l and are shoved inwardly until they come to rest against the guide post 2 and are locked in this position by means of socketed screws 17 arranged in the sectors to exert clamping pressure on the bits (see Figure The vtool is now ready to perform ythe boring operation and the work, is carried' out as described in connection with the boringl of an irregular passageway. L

If it should be desired to increase the .di-

Y ameter of a straight passageway beyond the capacity of the bitsas limited by their length, the inner wall of eachsector and cover plate is notched as at 18 in line with the slots 1l. With the sectors engaged with the post 2 and forming the Vbearing, the bits l2 areV adjusted by unscrewing'thescrews 17 and shims equal in width to the Vwidth of the lnotches 18 are fitted in the.v said notches between the bits` andagainst the central' post and the bits are shoved in against the shims, andl consequently project" outwardly a distance equal to the thickness of the s'hims.

yAfter all of the bits have VVbeen set in `this manner theyV are-locked by vmeansof theV vscrews 17 andthe driving head is ready for operation, itbeing understood that in this instance the adjacent endsy ofthe sectors also form the bearings through engagement vofthe shims with the central shaft.l

From the above description, it will be apparentthat I have produceda device possessing Athe features of advantage set forth' as desirable, and while I have described and claimed the preferred embodiment of the same, it is to be understood that I reserve the right to make all changes properly falling within the' spirit and scope of the appended claims.

I claim:

l. In a boring apparatus, the combination with acentral x'ed guide post, of a rotat able cutter head comprising a seriesY of resilient arms disposed around the post, a pair of sectors carried by pairs of said arms,

'means to springfthearms outward to dis-` pose .said lsectors to receive the guide post pairs of said arms, means to' expand said sectors to 'lit over the guide post,fradiallyar rangedoppositely disposed slots in said sec'- tors, bits sli'dable in said slots, and means to lock the bits in position with their inner endsv against said fixed guide post, said bits rotating around the post when the cutter head is'in operation'and being vfree to reciprocate inwardly or outwardly according to the .shape of the 'guide post. Y

3. In a'rboring apparatus, the combinationv with a driving shaft carrying a rotatablecutter head', a fixed'V center guide post, and- -r'adij ally arranged oppositely disposed bits slide ably mounted in said cut-ter head and'having l their inner ends inabutmentfwith said fixed guide post.and rotating around the sameV whenl the cutter head is in operation Vand be- Ving free toreciprocate inwardly or loutwardly according to the shape. of they guide post. lIn 'witness whereof l signa-ture.k

I hereunto my wILLiAM A. ,fammes- 

